This invention relates to a memory system with a sense circuit.
In a semiconductor memory using a one transistor-cell, a signal read out from the cell is of low level. Therefore, in the prior art memory system, a signal on a data line connected with a desired cell is applied to a preamplifier together with a reference signal on a data line connected with a dummy cell when word signals are applied to these cells. Then, the signal on a selected one of two data lines, which is amplified by the preamplifier is applied to a main amplifier connected with a common data line.
In such a memory system, the common data line having a large stray capacitance is driven by the pre-amplifier having a plurality of MOS (metal-oxide-semiconductor) transistors. Therefore, in order to achieve high speed reading, it is necessary to increase the conductance of these MOS transistors. However, since the increase of the conductance brings about an increase of the consumed power and the size of the system, the increase in conductance which is practically attainable has been limited.